ERROR:Microsoft Hyper-V VSS Writer has failed at prepare snapshot. The error is VSS_E_WRITERERROR_NONRETRYABLE. The code is: 0x800423f4

Hi Juan,

This is the error:

Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED)))

This means that the user configured to run the Hyper-V backups is not configured with all the required permissions.

Required permissions:

1. Create a Domain User for Hyper-V backups and recoveries.  The account only needs login name and password.
2. The Domain User account must be added to the these Active Directory Users and Computers Builtin security groups:
   1. Backup Operators
   2. Hyper-V Administrator
   3. Windows Authorization Access Group
   4. Users
   5. Remote Desktop Users
3. Also add the Group Policy Creator Owners security group to the Domain User account
4. On each cluster node, log in and perform steps to add the Domain User account to the local node’s
   1. Users group
   2. Administrators group
   3. Hyper-V Administrators group
5. Provide access for cluster management to the Domain User account, using the Grant-ClusterAccess PowerShell command.

Please let me know if you need any further information.

Thank you,

Carlos